Exposure Determination; Exposure Display - Nikon FM2 Instruction Manual

Exposure determination
The amount of light reaching the film plane is determined by a
combination of the shutter speed and the lens aperture. A
shutter speed of 1/500 sec. lets in twice as much light as a set-
ting of 1/1000 sec ., and only half as much light as 1/250 sec. An
aperture setting of 1111 lets in twice as much light as 1116, half as
much as 118. Thus, if the correct exposure for a particular
picture -taking situation is
1/500 at 1111, then 1/250 at 1116 or
111000 at 118 will give the same exposure. It is very convenient
to know this interrelation when considering depth of field. The
following table illustrates the interrelation between shutter
speed and aperture.
1/4000 112000 1/1000 1/500 1/250
4 5.6 8
11 16
Exposure display
The LED exposure indicator lamps can be seen on the right side
of the viewfield frame within the viewfinder. The shutter speed
number and IInumber in use are also visible. The LED exposure
display indicates exposure five ways, as shown in the table
below, in accordance with the conditions of each exposure.
Overexposure by more than 1 stop
Overexposure by 1/5 to 1 stop
Correct exposure
Underexposure by
1/5 to 1 stop
Underexposure by more than 1 stop
As correct exposure is approached, the LED exposure display
inside the viewfinder is liable to change rapidly and easily within
the very narrow range, so it is important to turn the lens aper-
ture ring and shutter speed dial carefully. Although intermediate
shutter speeds cannot be used, intermediate lens apertures
can-just turn the aperture ring for fine adjustment.
Note: When the shutter speed dial is set at
B
(bulb), the LEO exposure
display inside the viewfinder is turned off.
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